How do moisturizers work? Do they work at all? I have read that only if a moisturizer has been "electrolyzed" will its particles be small enough to penetrate your skin: otherwise, it just sits on top of your skin and locks in whatever moisture happens to be in it already. Is this true? And if so, are commercial moisturizers a con? How should I be moisturizing my skin?

-Balled by the claims of cosmetic companies

Dear Balled by the claims of cosmetic companies,

So many different moisturizing products are making contradictory claims that it's hard to know where to start in the quest for healthy skin. Does your skin need copper? Retinol? Emollients? How 'bout natural fruit enzymes or alpha-hydroxy acids? Before you dive into the ocean of smoothing, soothing lotions, it's important to understand that moisturizing your skin is a good idea.

Glands under the skin produce oils that are natural lubricants, working to keep the skin moist and supple. Soaps we use to wash our skin, however, remove these oils, along with dirt, leaving our skin drier. As people age, their bodies produce fewer natural oils, leading again to drier skin. Finally, exposure to the sun causes the skin to dry, discolor, freckle, and wrinkle. Finally, something that is a relatively new awareness is that prolonged exposure of unprotected skin can increase the risk of skin cancer.

Most moisturizers are mainly oil and water-based and work to keep moisture from escaping from the skin. No matter how much lotion you slather on, it won't put moisture back into your skin. The extra ingredients in moisturizers, the ones featured so prominently in ads, may offer some added benefits, but are usually more plump in price. Here are some common ingredients in moisturizers and their functions:

Sunscreen Any moisturizer you buy for daytime use needs to have sunscreen in it since sun damage is a leading cause of dry skin, wrinkles, and dark skin spots. Most dermatologists recommend a sunscreen with an SPF rating of 15 or higher for daily use.

Alpha-hydroxy acids
This ingredient helps wash away dead cells from the uppermost layers of skin, keeping pores clear and revealing new skin underneath. These natural fruit and plant acids can also help slow water loss and reduce the appearance of fine lines, though they may be a bit harsh on sensitive skin.

Tretinoin
This substance also helps the body replace old dead skin with new skin, and helps to lighten the skin. Retinoid creams often contain tretinoin, a vitamin A acid.

Sodium lauryl sulfate (SLS) or sodium laureth
This detergent additive is found in many cleaning products to help create lather or suds. These ingredients are to be avoided in moisturizers since they actually remove natural oil, drying your skin further.

Petrolatum
This is another common ingredient in moisturizers that reduces scaling of skin and helps skin retain moisture, but may be too harsh for some people, causing skin irritation.

With any moisturizer or skin/cosmetic product, if you experience any irritation or discomfort, stop using it and talk with your health care provider or dermatologist to find a viable substitute.